Devices and methods for imaging wells using phased array ultrasound

ABSTRACT

Methods and devices for imaging wells using phased array ultrasound imaging devices is described. The devices enable high resolution real-time imaging of a well during various operations in the well, including during completions, fracturing, milling, fishing and drilling operations. The phased array ultrasound imaging devices may be integrated with other well tools, such as a bottom hole assembly (BHA), fishing tools, milling tools, fracturing tools, and drilling tools, in order to integrate imaging capabilities into such tools.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of U.S. application. Ser. No.15/765,106, filed Mar. 30, 2018, which is a National Phase Applicationpursuant to 35 U.S.C. § 371 of International Application No.PCT/CA2016/051167, filed Oct. 6, 2016, which claims priority to U.S.Provisional Application No. 62/239,372, filed Oct. 9, 2015, each ofwhich is hereby incorporated by reference in its entirety.

FIELD OF THE INVENTION

The invention relates generally to well imaging, and more specificallyto imaging oil and gas wells using phased array ultrasound.

BACKGROUND OF THE INVENTION

There is a general need to obtain information and data regarding thestatus and condition of an oil and gas well during various welloperations, such as drilling, completion, production, maintenance andrepair. The information can be valuable in making informed decisionsregarding the well and futures wells, and in preventing andtroubleshooting any problems. Information can be gathered throughimaging devices which can help determine the condition of variousassemblies and components in the well, either as a preventative measureor when there is a suspected integrity issue. Well imaging can alsoprovide information on what components are in the well, and can captureinformation on any obstructions in the well. The data gathered from wellimaging is valuable for maximizing performance, recovery and efficiencyof a well, while minimizing environmental and safety risks.

Prior art methods of well imaging, such as cameras, calipers, leadimpression blocks and ultrasonic imaging devices, all have limitationswith regard to the quality of imaging data they can provide, and thespeed at which they can obtain such data. For example, cameras havelimited speed with which they can move through a well and captureimaging data. They are generally only practical when the location of anintegrity issue or obstruction in a well is already known, and thecamera simply needs to be deployed to that specific area to captureimages. Cameras also only work when there is clear water or gas in awell, which is rarely the case during many phases in the life of a well.Additionally, cameras are limited to only being able to capture imagesof the surface of the well, and cannot penetrate through opaque fluids,steel, cement or other materials found in wells.

Calipers are also used in well imaging, but calipers are only able toprovide low resolution measurements of the inside diameter of a well andcannot be used to obtain a detailed and intuitive image of a well. Leadimpression blocks and other mechanical imaging means such as thefish-imaging system in U.S. Pat. No. 8,294,758 can be used to obtainimaging information on “fish” or obstructions in a well, but they canonly give an impression of the surface of the obstruction and cannotprovide detailed information on the orientation and size of theobstruction. The data these systems provide is of limited use when thereare occlusions or obstructions with complex geometry.

Several oil and gas companies use an ultrasonic imaging device with aspinning head, for example the Ultrasonic Borehole Imager (UBI) ofSchlumberger. These devices have limited speed at which they canoperate, and generally only provide low resolution images at lowfrequencies. These spinning head tools are also required to becentralized in the well, which is challenging and often not possible indeviated wells

The prior art teaches that ultrasound technology can be used for generaldownhole imaging and measurement operations. See for example, U.S.Patent Publication No. 2009/0213690; Chinese Patent Application No.102128029; U.S. Patent Publication No. 2012/0176862; WO Publication No.2013/101694; U.S. Pat. No. 8,611,183; U.S. Pat. No. 6,483,777; ChinesePatent Application No. 102128028; U.S. Pat. No. 7,617,052; U.S. PatentPublication No. 2012/0127830; U.S. Patent Publication No. 2014/0050046;and U.S. Pat. No. 6,295,872.

The prior art contemplates imaging devices having a phased array design,such as U.S. Pat. No. 5,640,371 owned by Western Atlas International,Inc., Chinese Patent Application No. 101363314 and Chinese Patent No.200985790. Chinese Patent No. 202943014 describes a phase control roundarc array sound wave radiation unit that may be used for acousticlogging. Archer The Well Company also teaches the use of phased arrayultrasound technology for well operations (Archer The Well Company, TheSpace Series Brochure, R01/2011).

Importantly, prior art imaging methods, such as cameras, lead impressionblocks, and ultrasonic imaging devices, require separate deployment intoa well on a separate tool. This limits when imaging can occur duringwell operations, since imaging becomes a time-consuming and expensiveprocess since other tools must be removed from a well before an imagingtool can be deployed. As such, it is difficult and expensive to provideimaging of a well before, during and after completion operations andrecovery operations, as described in more detail below.

In Situ Well Pairs

Current in situ processes for recovering heavy oil typically use seriesof horizontal well pairs stacked on top of each other, the upper wellbeing used to inject heat and the lower well being used for production.FIG. 1 illustrates a typical in situ well pattern having three wellpairs 12, 14, 16 in a bitumen deposit 10. Generally, the well pair isdesigned such that the horizontal section of the injection well 12 a, 14a, 16 a is directly above (e.g. 4 to 10 meters above) the horizontalsection of the production well 12 b, 14 b, 16 b in each well pair. Laterin field life, additional “in-fill” wells 18 may be drilled, and aretypically located below the production well and slightly offset.

Referring to FIG. 2, each individual well, regardless of whether it isan injection well 20, production well 30 or in-fill well, generallycomprises:

-   -   A vertical section 22, 32 having a succession of solid steel        pipe sections (casing string) 22 a, 32 a held in place in the        wellbore by cement 22 b, 32 b.    -   A horizontal section 24, 34 having a succession of liner        sections (liner string) 24 a, 34 a, which are inserted into the        wellbore without cement. The liners are sections of steel pipe        with perforations, slots, screens or other openings to accept        the production fluids. This horizontal section is often referred        to as the “completion” and can be anywhere from a few meters in        length to over 1000 meters.    -   The individual sections of liners generally have a threaded        collar at each end for connection to adjacent liners. The        majority of the liner is patterned with features/openings which        allow bitumen to flow from the reservoir to the inside of the        liner in the case of production and in-fill wells, and for        steam/solvents/gases to flow from the liner to the reservoir in        the case of injection wells. The openings are very small to keep        sand and other small particulates from entering the liner.

Currently there are four general types of liners used in in situ wells:

-   -   1) Slotted liners have a number of thin slots cut into them, the        slots having widths as small as 0.012″.    -   2) Wire wrapped liners have holes of various types and sizes in        a steel pipe, with a wire wrapping on the outside of the pipe.        There may be multiple layers of wire wrapping.    -   3) Shrouded liners are similar to wire wrapped liners except        that a steel sheet which has had holes created in it, typically        by punching, is wrapped around the pipe. There may be multiple        layers of punched sheet steel.    -   4) Insert screen liners have circular wire mesh ‘plugs’ inserted        into a steel pipe.

Liners are generally screwed together to form a “liner string” andinserted into the open horizontal wellbore to form the completion.Typically the lower production well is drilled and completed before theupper injection well is drilled. To ensure consistent spacing andstacking of the injection well with respect to the production well, amagnetic ranging system is often used. A ranging tractor having aranging magnet is typically propelled through the lower production wellat the same time the upper injection well is being drilled. A detectoron the drill in the upper injection well determines the location of thedrill with respect to the ranging tractor in the lower production wellbased on the magnetic field emitted from the ranging magnet. Thiscombination of ranging magnet and detector enables the drilling operatorto guide the injection well drill so as to ensure that the injectionwell and production well are properly aligned with one another in termsof direction, orientation and distance from one another. After bothwells have been drilled and completed, the well pair is placed“on-production” by injecting steam/solvent/gases into the injectionwell.

There are several differences between in situ bitumen well pairs andtraditional oil and gas wells and therefore several unique problemsarise with in situ well pair completions. The features/openings in insitu well pair liners are much smaller than the features/openings intraditional wells and are therefore more susceptible to damage duringthe completion process. If these small features/openings are damaged,sand and other particulates can enter the well which reduces bitumenproduction and can compromise production/injectivity. Damage andsubsequent sand ingress, no matter what type of liner is used, blocksproduction/injection from not only the damaged area, but all areasupstream for the injector and downstream for the producer. Damage duringthe completions process can include damage to the screwed connections(joints) between individual sections of liners; damage to the slots,holes or features of the liners; damage to the external features of theliners such as wire wrapping, shrouds and external facing parts of theslots, including partial or full removal of the wire wrapping, shroudsor plugs; and deformation of some or all the sections of the liner dueto mechanical stress through compression, tension and torsion.Furthermore the small distance between well pairs (˜5 m) means thatsmall defects can quickly create steam channels which can seriouslydamage wells

There is a need to determine the condition of liner strings in in situwell pairs after completion and prior to the well being placed onproduction. There is a need for systems and methods to determine thestatus and condition of liner strings in in situ well pairs after theliner string has been positioned in the wellbore in order to assess anydamage and take appropriate measures before the well pair is placedon-production. Importantly, there are several differences in imagingliner strings as compared to imaging conventional wells due to theunique conditions of in situ well pairs, including the very finefeatures found in liner strings, and the orientation and placement of insitu well pairs. In addition, there has been a need for systems andmethods that improve the efficiency by which liners are placed in a wellin which the overall number of steps to drill and complete a well isreduced.

Perforated and Multi-Stage Hydraulically Fractured Wells

Completion operations during production refers to the operationsperformed after drilling to prepare an oil or gas well for production.Completion operations often involve running in a completion string,perforating the casing and/or liner, and stimulating the well, which mayinvolve acidizing and/or hydraulic fracturing.

In horizontal wells, “plug-and-perf” fracturing operations are commonfor fracturing multiple locations in the wellbore. In plug-and-perfoperations, a plug is pumped into the wellbore to the desired depth,typically near the toe of the well. The plug is activated to seal off adownhole section of the wellbore from an uphole section of the wellboreand perforations are created in the well casing, uphole of the plug, toallow fluid flow between the inside of the casing and the surroundingformation. Perforations can be created in a variety of ways, includingusing explosives and a perforating gun, using rupture discs that areruptured through the application of fluid pressure downhole, or usingacid or abrasives such as sand to open up perforations. Afterperforations have been created, fracturing fluid is pumped downhole tofracture the formation adjacent the perforations. The plug prevents thefracturing fluid from flowing into the wellbore section downhole fromthe plug. After fracturing, the plug is deactivated such that thefracturing stage for a particular zone of the well is complete. Thisprocess may then repeated in stages moving uphole towards the heel ofthe well until all fractures are complete in all of the zones ofinterest.

Instead of “plug-and-perf” operations, a well may be fractured using acoiled tubing or rig deployed system that is run into the well. In thissystem, the coiled tubing is typically set up to contain packers atvarious intervals that can be set in sequence to isolate a section ofthe wellbore. After a packer is set, perforations or openings can becreated uphole of the packer, similar to plug-and-perf operations, toallow fracturing to be undertaken uphole of the packer. The packers canbe set in sequence from a downhole end of the coiled tubing/rig to anuphole end to allow fracturing to proceed in stages. There are a numberof systems that can be configured to a coiled tubing string forisolating zones, opening the coiled tubing, perforating any well casingand undertaking the fracturing operations.

After completion operations have finished, it is often desirable todetermine the condition of the completion. Various imaging tools, suchas a camera or calipers, allow for such a determination, however theyare generally only deployed into the wellbore after all completionoperations have taken place. In order to determine the condition of thecompletion in the middle of completion operations, the entire completionstring generally needs to be pulled from the wellbore and a separateimaging tool run-in, after which the imaging tool needs to be removedand the completion string run back into the wellbore to finishcompletion operations. This is very time-consuming and costly, and thusis typically avoided during completion operations unless a major problemoccurs. This is particularly true during fracturing operations, due tothe cost associated with paying a fracturing crew to stand-by while thecompletion string is removed and the imaging tool run-in.

Accordingly, it is generally desirable to determine the condition of acompletion during fracturing operations, and specifically to determinethe status and condition of the fracturing ports and perforations.Ports/perforations may be damaged or eroded during fracturing, andintact ports/perforations are essential for effective fracturingoperations. Therefore it is particularly valuable to determine thecondition of the completion immediately after fracturing has occurred,since there is generally a rapid change in conditions after fracturinghas ceased. As such, any time lag between the end of fracturing and thecapture of imaging data generally decreases the value of the imagingdata obtained. Current technology that requires the completions stringto be removed and a separate imaging system to be run-in does not allowfor imaging to occur immediately after fracturing.

Information captured immediately after each stage of fracturing and/orafter all fracturing stages have finished has enormous value indesigning and configuring future fracturing stages and operations. Forfracturing operations using pumped perforation fracturing processeswhere the plug assembly can be removed after each fracturing stage, thisinformation is especially valuable since further fracturing stages canbe modified based on the imaging information gathered. For other typesof fracturing operations, such as coil or rig deployedperforation/isolation strings, the information gathered after eachfracturing stage and at the end of all the stages can be used fordesigning and configuring future fracturing operations.

Accordingly, there is a need for systems and methods for imaging acompletion string that is quick, reliable, relatively inexpensive, anddoesn't require the removal of the completions string and the deploymentof a separate imaging tool. There is a further need for systems andmethods that can capture imaging information from a completionimmediately before and after each fracturing stage and before and afterthe entire fracturing operation.

Recovery Operations

Recovery operations are used to retrieve objects and equipment lostdownhole in a well, to open up damaged casing, and/or to clearobstructions, items and debris from a wellbore. Recovery operationsinclude fishing, milling, swaging, and more.

Fishing is a common recovery process used in oil and gas wells toretrieve objects and equipment lost downhole. Any equipment sentdownhole can be a “fish”, including drillpipe, casing, bottom holeassemblies (BHAs), parts of BHAs and wireline tools. Fishing is arelatively expensive process due to the cost of fishing equipment,personnel, lost production time and most significantly, the cost of adrill rig or service rig used in the operation. A significant part ofthe fishing operations is the characterization of the fish, i.e. whatthe fish is and how it is positioned in the well, including what thefish looks like from the uphole side.

Currently, there are three general ways to characterize a fish. Thefirst way is to estimate what the fish is based on what equipment hasbeen recovered and what is missing. This is generally the fastestmethod, however the most imprecise. The second way to characterize afish is to use an impression block. An impression block is a malleableblock, typically made of lead, that is sent downhole and pressed on thetop of the fish to get an impression of the top of the fish. There areseveral limitations and disadvantages to using an impression block. Forexample, an impression block does not provide comprehensive informationon the fish since it only gives an impression of the top few millimetersof the fish. An impression can also be damaged or altered as it is beingremoved from the well, and the malleability of the block is limited. Inwells with higher temperatures, the impression block may be too soft toperform adequately. Additionally, as is the case in all current imagingtools generally used, the impression block requires a separate trip intothe well with a separate tool for gathering the impression, therebyincreasing the time and cost of the fishing operation.

A third way to characterize a fish is to deploy a camera downhole toprovide a visual picture of the top of the fish. However there are anumber of limitations to cameras. Importantly, a camera requires a clearfluid on top of the fish to obtain an image of the fish. This mayrequire that opaque fluids are removed from the well, which can be verydifficult to achieve and generally increases the cost of the fishingoperation. Replacing fluids is particularly challenging where opaquedrilling mud acts as pressure control, and displacing the drilling mudcan pose a safety risk. Additionally, cameras require a separate tripinto the well with a separate tool to obtain the images, therebyincreasing the time and cost of the fishing operation.

After the nature of the fish has been determined, a number of differenttypes of recovery equipment can be deployed depending on the nature ofthe fish. Commonly used tools include magnetic fishing tools, junkbaskets, fishing spears, overshot tools, mills, and more. Casing swagesmay also be used in recovery operations where there is damaged casing inorder to open up or clear the casing.

Milling Operations

Milling is a common process used in oil and gas wells to remove items,obstructions or debris from a wellbore which cannot be recovered throughfishing. Milling is also used to create a hole in an existing piece ofcasing or completion for the purposes of “sidetracking” the well.Sidetracking is the process of creating an alternative path or branchfor the well either because there is a requirement for more branches (amultilateral well) or the existing path of the well is damaged and a newpath is required. The hole that is milled in the existingcasing/completion is called the “window”. It is generally valuable toobtain information on the milling process, such as the shape, locationand orientation of the window, and any lips or features around thewindow that may affect subsequent drilling operations. It is alsovaluable to ascertain information on the debris, items or obstructionsin the wellbore in order to make the best decision regarding the type ofmilling tool to use, and to confirm that a milling operation has beensuccessful in removing debris, items or obstructions from the wellbore.It is also valuable to ascertain whether any damage has been created inthe wellbore by the debris, items or obstructions or by the millingprocess.

Currently, information regarding milling operations can only be gatheredthrough the use of a camera that is deployed into the wellbore on aseparate tool from the milling tool. This requires that the milling toolbe removed from a wellbore before a camera is deployed, thus requiringmultiple trips into the wellbore to gather information before, during orafter milling operations, increasing the time and costs involved. Forexample, if an operator wants to obtain comprehensive information aboutmilling operations for removing an obstruction from a well, they maydeploy a camera into a wellbore prior to milling to obtain crude imageson the location, position, type and size of the obstruction in order tomake decisions on the milling operations. The camera would then removedfrom the wellbore and a milling tool, for e.g. a taper mill or junkmill, would be deployed into the well to grind up the obstruction. Themilling tool is then removed and the camera is redeployed to confirmthat the obstruction has been cleared from the well, and to ascertainwhether any damage has been done to the wellbore. If the obstruction hasnot been sufficiently cleared, the milling tool or another tool isdeployed to finish the clearing, after which the camera is redeployed toconfirm that the well is cleared and to ascertain any damage to thewell. The multiple trips with the camera greatly increases the cost andtime involved in milling operations, and thus is typically only donewhen a problem is encountered. In this case, milling operations would beconducted without first obtaining imaging data on the obstruction, whichcan decrease the chance of success of the milling operation sincemilling is conducted blindly without having information about theobstruction. Additionally, if imaging data is not gathered aftermilling, there may be damage to the wellbore that is not known, whichmay affect subsequent well operations and cause problems in the future.

Drilling Operations

During drilling, it is generally desirable to obtain information on theformation through which drilling is occurring, and the condition andstructure of the borehole after it is drilled. Due to the generally lowdata rates to surface during drilling operations, simple formationevaluation tools can be used to relay data during drilling operations tothe surface. These fall under two broad categories, MWD (measurementwhile drilling) which covers geospatial and speed data, and LWD (loggingwhile drilling), which covers formation evaluation. Dual elementacoustic tools for caliper measurements are common in LWD applications.

Summary

In summary, there is a general need for a downhole imaging system thatcan gather high resolution real time images of a wellbore during variouswell operations. The value of such information is further enhanced whenthis imaging information can be gathered as part of the existingdrilling/completing/maintenance processes. Collecting this informationas part of the process saves time and money by eliminating the need fora separate deployment process to collect downhole data. Furthermore, inthe case of completions processes, there has been a need for a baselineimage of the well to be obtained directly after the well has beencompleted, allowing future imaging scans to be compared to thisbaseline.

SUMMARY OF THE INVENTION

In an aspect of the invention, there is provided a method for imaging anin-situ heavy oil well production liner string before the well is placedon production, the well comprising a substantially horizontal section,the method comprising the steps of: a) inserting a phased arrayultrasound imaging system into the well; and b) moving the imagingsystem through the liner string in the substantially horizontal sectionof the well while activating the imaging system to generate athree-dimensional image of the liner string; wherein thethree-dimensional image of the liner string can be used to assess thecondition of the liner string. Steps a) and b) may be undertaken duringa well completions process and/or the well may contain brine or waterbased drilling mud during imaging. The phased array ultrasound imagingsystem may have a ring-shape or radial transducer. The imaging systemmay include a ranging system operatively connected to the imagingsystem, and steps a) and b) may occur during ranging operations as asecond well is being drilled adjacent to the well, and/or after rangingoperations have been completed and the imaging system and ranging systemare being removed from the well.

In an aspect of the invention, there is provided a device for imaging anin-situ heavy oil well production liner string during completionsoperations comprising: a body adapted for movement through the linerstring; a downhole tractor operatively connected to the body forproviding motive power to move the device through the liner string; anda phased array ultrasound imaging system operatively connected to thebody for generating a three-dimensional image of the liner string thatcan be used to assess the condition of the liner string. The phasedarray ultrasound imaging system may have a ring-shaped or radialtransducer. The device may further comprise a ranging system operativelyconnected to the body for guiding a drill in a second well as the secondwell is being drilled. The ranging system may include a ranging magnet.

In an aspect of the invention, there is provided a method for imaging awellbore liner during fracturing operations comprising the steps of: a)deploying an imaging/isolation device having a phased array ultrasoundimaging system and an isolation device into a wellbore to a firstlocation; b) activating the isolation device to seal a downhole sectionof the wellbore containing the imaging system from an uphole section; c)perforating the wellbore liner uphole of the isolation device andfracturing the formation adjacent the perforations; d) deactivating theisolation system and advancing the imaging/isolation device at leastpartially uphole while imaging the wellbore liner where the perforationand fracturing occurred; and e) repeating steps b) to d) untilfracturing operations are complete; wherein imaging the wellbore linerprovides information that can be used to assess the condition of theliner string after fracturing has occurred. In step c), the perforationsin the wellbore liner may be imaged after perforation but beforefracturing. In step d) the imaging/isolation device may be pulled to thewell surface and step a) repeated. In step a), an image of the wellboreliner may be taken while the device is being deployed. The isolationdevice may be a plug or a packer element.

In an aspect of the invention, there is provided a device for imaging awellbore liner during fracturing operations comprising: a phased arrayultrasound imaging system for generating an image of the liner stringbefore and/or after a fracturing stage has occurred to assess thecondition of the liner string; an activatable isolation elementoperatively connected to the imaging system, wherein activating theisolation element seals a downhole section of the wellbore from anuphole section of the wellbore to enable fracturing operations to occur,and deactivating the isolation element unseals the downhole section fromthe uphole section; and a deployment system operatively connected to theisolation element and/or the imaging system for deploying and removingthe device from the wellbore. The imaging system may be located downholeof the isolation element to prevent fracturing fluids and high pressuresfrom contacting the imaging system during fracturing operations. Theisolation element may be a packer element or a plug. The deploymentsystem may be coiled tubing, wireline or a service rig. The device mayfurther comprise a perforation system for perforating the wellbore lineruphole from the isolation element.

In an aspect of the invention, there is provided a method for imaging awellbore during recovery, milling or drilling operations comprising thesteps of: a) deploying a recovery, milling or drilling tool having atleast one integrated phased array ultrasound imaging system into thewellbore; and b) moving the recovery, milling or drilling tool throughthe wellbore while activating the at least one imaging system togenerate images of the area in the wellbore in which recovery, millingor drilling operations are occurring. The at least one imaging systemmay have a forward facing transducer array wherein the generated imagesare of the area downhole of the tool, and/or the at least one imagingsystem may have a radial or ring-shaped transducer array wherein thegenerated images are of the area radial to the tool. The recovery,milling or drilling operations may be fishing operations where the toolis a fishing tool. The at least one imaging system may be activatedwhile a fish is being recovered to enable better placement of thefishing tool relative to the fish. Alternatively, the recovery, millingor drilling tool is a casing swage, allowing for the at least oneimaging system to be activated while casing is being swaged to obtain animage of the casing during swaging operations. Alternatively, the toolis a milling tool, such as a taper mill or a junk mill. The tool mayalso be a bottom hole assembly (BHA) adapted for operative connection toa drill string for drilling operations.

In an aspect of the invention, there is provided a device for imaging awellbore during recovery, milling or drilling operations comprising: arecovery, milling or drilling tool adapted for movement through thewellbore and for recovery, milling or drilling operations in thewellbore; and at least one phased array ultrasound imaging systemoperatively connected to the recovery, milling or drilling tool forgenerating images within the wellbore. The at least one phased arrayultrasound imaging system may comprise a ring-shaped or radialtransducer array for obtaining images of the wellbore as the device ismoved through the wellbore, and/or a forward facing transducer array,which may be at a downhole end of the tool for obtaining images of thevolume located downhole of the device. The tool may be a fishing tool ora casing swage. In the case of a fishing tool, it may be a magneticfishing tool, a junk basket, a fishing spear, or an overshot fishingtool. The tool may also be a milling tool, such as a taper mill or junkmill, or a bottom hole assembly adapted for operative connection to adrill string.

BRIEF DESCRIPTION OF THE DRAWINGS

Various objects, features and advantages of the invention will beapparent from the following description of particular embodiments of theinvention, as illustrated in the accompanying drawings. The drawings arenot necessarily to scale, emphasis instead being placed uponillustrating the principles of various embodiments of the invention.Similar reference numerals indicate similar components.

FIG. 1 is a schematic cross-sectional front view of a bitumen formationillustrating a typical prior art in situ well pattern, having three wellpairs of upper injection wells and lower production wells, withadditional in-fill wells.

FIG. 2 is a schematic cross-sectional side view of an in situ well pairof the prior art having an upper injection well and a lower productionwell. Each well has a vertical section with casing cemented in thewellbore and a horizontal section having a liner string.

FIG. 3 is a schematic side view of a downhole device having a tractor, aphased array radial ultrasound tool and a ranging magnet.

FIG. 4 is a schematic side view of the downhole device of FIG. 3 inoperation, wherein the device is being propelled through a completedlower production well as an upper injection well is being drilled.

FIG. 5 is a flowchart illustrating a method for imaging a liner stringin an in situ well.

FIG. 6 is a flowchart illustrating a method for imaging a liner stringof an in situ well pair using a device having imaging and rangingfunctions.

FIG. 7 is a schematic cross-sectional side view of an imaging andfracturing device positioned in a wellbore.

FIG. 8 is a flow-chart of a method for imaging and fracturing ahydrocarbon formation.

FIG. 9A is a schematic cross-sectional side view of a magnetic fishingtool containing a phased array ultrasound imaging device.

FIG. 9B is a schematic cross-sectional side view of a junk magnetfishing tool containing a phased array ultrasound imaging device.

FIG. 9C is a schematic side view of a fishing spear tool containing aphased array ultrasound imaging device.

FIG. 9D is a schematic cross-sectional side view of an overshot typefishing tool containing a phased array ultrasound imaging device.

FIG. 9E is a schematic side view of a casing swage containing a phasedarray ultrasound imaging device.

FIG. 10A is a schematic side view of a taper mill containing two phasedarray ultrasound imaging devices.

FIG. 10B is a schematic cross-sectional side view of a junk millcontaining a phased array ultrasound imaging device.

FIG. 11 is a schematic cross-sectional side view of a bottom holeassembly (BHA) containing two phased array ultrasound imaging device.

FIG. 12 is a schematic cross-sectional side view of a drill stringcomprising the BHA of FIG. 11, the drill string being in a boreholehaving a washout area.

FIG. 13 is a schematic cross-sectional side view of a drill stringcomprising the BHA of FIG. 11, the drill string being in a boreholehaving a drill cuttings build up area.

DETAILED DESCRIPTION OF THE INVENTION

Various aspects of the invention will now be described with reference tothe figures. For the purposes of illustration, components depicted inthe figures are not necessarily drawn to scale. Instead, emphasis isplaced on highlighting the various contributions of the components tothe functionality of various aspects of the invention. A number ofpossible alternative features are introduced during the course of thisdescription. It is to be understood that, according to the knowledge andjudgment of persons skilled in the art, such alternative features may besubstituted in various combinations to arrive at different embodimentsof the present invention.

With reference to the figures, systems and methods for imaginghydrocarbon wells using phased array ultrasound technology aredescribed. The systems and methods can be used during various welloperations, including drilling, completion and production operations.The systems generally comprise one or more phased array ultrasoundimaging devices that can be integrated with other tools depending on thespecific operations that are being performed alongside the imaging.Integrating the phased array imaging device with other tools allows forimaging to occur during operations where it may traditionally bedifficult to obtain imaging data, such as drilling, fracturing, fishing,milling, and more.

Phased Array Ultrasound Imaging Device

In accordance with the invention, a phased array ultrasound imagingdevice is used in the systems and methods for imaging wells.

Phased array ultrasound is an advanced method of ultrasonic testing thathas several advantages over conventional non-phased array ultrasoundtechnology. Conventional ultrasound technology uses a single-element(monolithic) probe that emits a beam in a fixed direction. To test orinterrogate a large volume of material, the probe must be physicallyscanned/moved/turned/rotated to sweep the beam through the area ofinterest. In contrast, the beam from a phased array probe can be movedelectronically without moving the probe, and can be swept through a wide3-dimensional area at high speed. The beam is controllable because aphased array probe is made up of multiple small elements, each of whichcan be pulsed individually with computer-calculated timing. The term“phased” refers to the timing, and the term “array” refers to themultiple elements.

The phased array ultrasound imaging device of the invention generallyincludes one or more phased array ultrasonic transducer arrays andassociated processing electronics. The transducer array convertselectrical energy into sound to emit ultrasonic sound waves (i.e. above18 kHz). Generally 0.5 to 10 MHz waves are used in the imaging system,however frequencies outside of this range may be used for certainapplications. The transducer preferably comprises a plurality ofindividual piezoelectric (PZT) elements that transmit and receiveultrasonic pulses independently and can be timed in a sequence to set upa pattern of constructive interference resulting in a beam that can besteered electronically.

The imaging system may be battery powered or receive power from thesurface, or both. The data from the imaging system may be conveyeduphole to the well surface through a transmission line or using wirelesscommunication technology for immediate viewing. The data may also bestored onboard the imaging system for later retrieval in the event of acommunication loss. The imaging system may record images continually orit may be triggered manually and/or automatically, such as through theuse of movement triggers.

Specific Applications of the Phased Array Ultrasonic Imaging DeviceDevice for Imaging Liner String

In one embodiment, the phased array ultrasonic imaging device is usedfor imaging well liners. FIGS. 3 and 4 illustrates an imaging tool 50incorporating the ultrasonic imaging device that can be used for imagingin situ well pair liners. The imaging tool generally comprises aconveyance system 60, an imaging system 70 and a ranging system 80.

In one embodiment, the conveyance system 60 comprises a downhole or welltractor having a body 62 and a plurality of wheel or drive sections 64extending out of the body that abut against the inner wall 98 of thewell casing or liner and are driven to push the well tractor through thewell casing. At least one motor is situated in the body, and preferablyeach wheel or drive section has its own motor for independently drivingeach wheel. The conveyance system provides the motive power to drive thedevice 50 along horizontal sections of the wellbore, where gravitycannot be relied upon to move the device.

The imaging system 70 incorporates the phased array ultrasonic imagingdevice previously described, preferably using a ring-shaped or radialtransducer array, which allows for a 3-dimensional image of the linerstring to be produced with sufficient resolution to show the very finedetails in the liner string, including the smallest slots which may be0.012″ wide.

The ranging system 80 comprises a ranging magnet 82 that emits amagnetic field 88 that can be detected by a detector 90 on a drill 92 toquantify the distance and direction of the detector from the magnet.Ranging systems are generally known to those skilled in the art fordrilling wells to guide the drilling of a second well 94 with respect toa first well 96. Magnets are the most commonly used ranging tool, butothers, including the use of radioactive sources and magnetized liners,may also be used.

The tool 50 may also comprise centralizing rods 84 that extend outwardlyfrom the body of the tool and abut the inner wall 98 of the well casingor liner to keep the device in the center of the wellbore 100. Othermeans for keeping the device centralized in the wellbore could also beused.

In one embodiment, a cable 86 is operatively connected to the device toprovide power to the conveyance system 60 and/or the imaging system 70and to transmit information between the device and the well surface. Thecable can also be used to tow the device through the liner string and/orthe vertical section of the wellbore towards the well surface whenrecovering the device.

Method for Imaging Liner String

With reference to FIGS. 5 and 6, a method for imaging a liner string ofan in situ well, such as a SAGD well, is described.

Initially, an in situ well having a vertical section and a horizontalsection is drilled and casing is cemented into the vertical section ofthe well in accordance with known procedures. A liner string comprisinga plurality of liners is inserted into the horizontal section of thewell (i.e. the well is completed). Before the well is placed onproduction, imaging of the liner string takes place using the phasedarray ultrasound tool to create a 3D digital image of the entire linerstring. The image is viewed to detect the condition of the liner stringand/or if sand is present in the liner string to determine if remedialaction needs to be taken prior to production.

In one embodiment, the imaging of the liner string occurs during thecompletion process when there are fluids present in the liner string andthe well is generally at or close to ambient pressure and temperature.Typically, the fluids are brine or water based drilling muds. By imagingthe liner string during the completions process instead of in a separatestep, and by being able to provide clear images of sufficient resolutionthrough the fluids that are present instead of having to remove thefluids, there are significant savings in terms of time and costassociated with imaging the liner string. The images provided by thephased array ultrasound tool of the liner can be used to identifydefects in the liner string such as damage to slots, wire wrapping, orcollar threading, mechanical damage and/or abrasion. They can also beused to identify if there is sand in the liner string.

In one embodiment, the imaging of the liner string is combined withranging operations as outlined in FIG. 6. In this embodiment, an imagingdevice having both magnetic ranging capabilities and phased arrayultrasound capabilities (such as the device illustrated in FIGS. 3 and 4and described above) is propelled through a completed lower productionwell while an upper injection well is being drilled. The imaging of theproduction well liner can occur as the ranging operations are occurringand the imaging device is being driven downhole, or the imaging canoccur as the imaging device is recovered back to the surface of thewell. The imaging can also occur during both phases, i.e. duringdownhole and uphole movement of the imaging device. In this embodiment,after the upper injection well is completed, the imaging device ispropelled through the injection well for imaging the injection wellliner. Typically the ranging capabilities of the imaging device are notneeded in the upper well since the lower well is already drilled,however the same device can be used. Alternatively, a different imagingdevice without ranging capabilities but with phased array ultrasoundcapabilities can be used to image the upper well liner.

In the embodiment shown in FIG. 6, combining ranging and imagingoperations into one step results in significant savings in terms of timeand money as separate completion steps are undertaken at the same time.

Device for Imaging Wells During Completion Operations

In another embodiment, the phased array ultrasound imaging device isintegrated into a completions string for imaging a well duringcompletion operations. The imaging device may be retrofit into anexisting completions string, or a completions string designed tospecifically incorporate the imaging device may be built. Incorporatingthe imaging system into a completions string advantageously allows forimaging of a wellbore liner to occur during completion operationswithout having to deploy a separate imaging system, and specificallyallows for the imaging of fracturing ports and perforations immediatelybefore and after fracturing.

FIG. 7 illustrates one embodiment of the invention wherein a phasedarray ultrasonic imaging device 112 as previously described isintegrated into a combined imaging and fracturing device 110. The phasedarray ultrasonic imaging device 112 preferably includes a ring shaped orradial transducer that can generate a 3D image of the wellbore liner,showing any changes to the perforations in the liner and any otherfeatures and defects in the liner.

As illustrated in FIG. 7, the imaging/fracturing device 110 is deployedin a wellbore liner 102 having a toe 104 at the downhole end of thewellbore and a heel 106 marking the transition between the wellbore'shorizontal and vertical zones. Besides the imaging system 112, theimaging/fracturing device 110 includes, an isolation element 114 and adeployment system 116. The imaging/fracturing device may optionallyinclude a centralizing element 118 and a perforating system 120.

Preferably, the imaging device 112 is operatively connected to thedownstream side of the isolation element 114, which shields the imagingsystem from contact with high pressure and abrasive fracturing fluidslocated on the upstream side of the isolation during hydraulicfracturing operations, thereby prolonging the life and reliability ofthe imaging device.

When the imaging/fracturing device 110 is positioned in a liner string,the isolation element 114 can be activated or set to create a tightannular seal within a liner string to seal a downhole section of theliner string from an uphole section during fracturing operations. Theisolation element can be one of several types of isolations that areused in fracturing operations, such as a plug or a packer element asknown by those skilled in the art. For example, these may includeexpandable and resealable/resetable packers and plugs which can beexpanded and contracted multiple times without loss of pressureisolation ability.

The deployment system 116 is operatively connected to the isolationelement 114 and/or imaging device 112 to enable the imaging/fracturingdevice 110 to be run into and removed from the wellbore. Generally thedeployment system is a wireline or coiled tubing that may bespecifically adapted for these operations. Other deployment systems thatare known to those skilled in the art can also be used, such as downholetractors, service rigs, and pumped plug systems.

The centralizing element 118 is designed to keep the imaging/fracturingdevice 10 in the center of the wellbore. FIG. 7 illustrates oneembodiment of a centralizing element, wherein the element includescentralizing rods 118 a that extend from a body 118 b and abut the innerwall of the well casing or liner to keep the imaging/fracturing devicein the center of the wellbore.

Other means for keeping the device centralized in the wellbore can alsobe used, including the inherent stiffness of the completions string,especially if deployed on coiled tubing or a service rig. Alternatively,two centralizers can be used in conjunction with two knuckle joints inorder to centralize the imaging system independently from the isolationelement and deployment system. The two centralizers serve to centralizethe imaging device while the knuckle joints allow for freedom ofmovement between the imaging system and other components.

The imaging/fracturing device 110 may optionally include a perforatingsystem 120 positioned uphole of the isolation element 114 for creatingperforations 108 in the liner and/or casing during fracturingoperations. In one embodiment, the perforating system is a perforatinggun containing charges/explosives. Examples of various perforatingsystems include high pressure sand, acid, burst discs and explosives.

Method for Imaging Wells During Fracturing Operations

With reference to FIG. 8, a method for imaging a liner string duringfracturing operations in a well is described.

After a well has been drilled and a casing and liner string have beenrun into the well, an imaging/fracturing device as described above andone embodiment of which is shown in FIG. 7 is run into the liner stringto the desired location. While the device is being run in, the imagingsystem can capture an image of the liner/completion string to determinethe condition of the string prior to perforating.

Next, the isolation element in the device is activated to seal adownhole section of the liner string from an uphole section.Perforations are created using known perforation techniques followedoptionally by imaging of the perforations by unsetting the isolationelement, moving the imaging system uphole to the perforations, thenmoving the imaging system back downhole and resetting the isolationelement prior to hydraulic fracturing. Then fracturing operationscommence by pumping hydraulic fracturing fluid downhole at high pressureto complete the first stage of fracturing. The isolation elementprevents the fracturing fluid from entering the downhole section of theliner string, thus causing the fracturing fluid to exit the linerthrough the perforations, where it enters the surrounding formation tofracture the formation.

After the first stage of fracturing is complete, the isolation elementis deactivated. At this point, depending on the fracturing system beingused, the imaging/fracturing device, including the isolation element, iseither moved uphole to the well surface, or moved uphole to the nextfracture area or zone of interest. In a pumped plug system that uses aplug as the isolation element, the device is generally recovered to thewell surface, whereas in a coil/rig deployed system that uses a packeras the isolation element, the device is generally moved uphole to thenext fracture area.

After the first stage of fracturing is complete, the procedure isrepeated for each subsequent fracture area or zone of interest. If theimaging/fracturing device was moved uphole only to the next fracturearea, the procedure is repeated starting with setting the isolationelement in the new location. If the imaging/fracturing device was movedto the well surface, it is deployed downhole again to the next fracturearea, and an image may be captured by the imaging system as it movesdownhole to provide information on the condition of the liner stringright before the next fracturing stage.

The images and information generated by the imaging system can be usedto identify the condition of the general mechanical installation of theliner string, such as identifying damage and leaks. It can also be usedto identify the condition of the fracturing ports and perforations andtheir changes during the fracturing process, and specifically toidentify if any damage or erosion has occurred during the fracturingprocess. Problems related to the completions integrity, includingpinched liners caused be geological movements, damaged or loose collars,and sand intrusion can also be identified.

In one embodiment, the imaging of the liner string occurs right afterfracturing is finished when there are fracturing fluids present in theliner string and the well is generally at or close to ambient pressureand temperature. The fracturing fluids may be water or hydrocarbon-basedfracturing fluids, and may include various additives such as propants,gases, viscosifying agents, breakers, buffering agents, clay controlagents, and more. Using a phased array ultrasound imaging system allowsimaging to occur through opaque fluids.

By imaging the liner string during the completions process instead of ina separate step, and by being able to provide clear images of sufficientresolution through the fluids that are present instead of having toremove the fluids, there are significant savings in terms of time andcost associated with imaging the liner string.

Imaging Wells During Recovery Operations

In another embodiment, the phased array ultrasound imaging device isintegrated with equipment used in recovery operations, such as fishingtools, milling tools and casing swages, to enable imaging duringrecovery operations.

FIGS. 9A, 9B, 9C, 9D and 9E illustrate various embodiments forintegrating one or more phased array ultrasound imaging device oncommonly used recovery tools. The imaging devices may include variousshaped transducer arrays, such as forward facing transducer arrays forobtaining imaging data from the volume in front of the array, and/orradial transducer arrays for obtaining imaging data in the radial areaaround the transducer and fishing tool.

FIG. 9A illustrates a magnetic fishing tool 202 comprising a pluralityof magnets 204 and an integrated phased array ultrasound imaging device206 having a forward facing transducer array for imaging an area infront of the imaging device shown by arrows 206 a.

FIG. 9B illustrates a junk basket fishing tool 208 that drives smallitems around the outside of the tool and into a basket 210 on the tool,shown by the arrows 212. A phased array ultrasound imaging device 214having a forward facing transducer is integrated into the tool toprovide imaging data on the “junk” or items located in the well in frontof the tool, shown by arrows 214 a.

FIG. 9C illustrates a spear-type fishing tool 218 that is generally usedto recover large tubular fish by inserting a spear tip 220 into theinside of the fish and attaching to the fish using a set of extendibleslips (not shown). A phased array ultrasound imaging device 222 having aforward facing transducer is integrated into the tool to provide imagingdata on the fish and help align the spear with the fish. In thisexample, the imaging device obtains imaging data from the area in frontof the transducer array shown by arrows 222 a.

FIG. 9D illustrates an overshot type fishing tool 224 comprising a largediameter, open mouth pipe 226 that surrounds the outside of the fish tograb the fish. A phased array ultrasound imaging device 228 having aforward facing transducer array is integrated into the tool to obtainimaging data on the fish and to align the fish with the mouth of thepipe. In this example, the imaging device obtains imaging data from thearea in front of the transducer array shown by arrows 228 a.

The phased array ultrasound imaging device may also be integrated with acasing swage tool, an example of which is shown in FIG. 9E. The casingswage tool 230 generally has a tapered nose 232 used to open collapsedcasing and/or make a swage run prior to running a production tool toensure the inner diameter of the casing is clear. The casing swageincludes an integrated phased array imaging device 234 having aradial-shaped or ring transducer for imaging the inner diameter of thewellbore and/or the casing in the radial area surrounding the ringtransducer shown by arrows 234 a.

While the fishing tools shown in FIGS. 9A, 9B and 9D illustrate thephased array ultrasound imaging device located in the centre of thetool, the imaging device may also be offset to one side of the tool,i.e. off centre. Having the imaging device off centre allows for imagingdata to be gathered from multiple angles when the tool is rotated in thewell. This imaging data can then be merged to create a higher qualityimage of the fish or the area being imaged, since there is lesslikelihood of missing data due to occlusions, and more precisemeasurements available due to decreased ultrasonic artifacts.

During recovery operations, the phased array ultrasound imaging deviceprovides high resolution real time images of any obstructions in thewell and the surrounding area, thereby providing detailed information onthe obstruction, which increases the efficiency and effectiveness ofrecovery operations. Integrating the imaging device into a recovery toolallows information to be gathered on the obstruction and the obstructionto be recovered or opened up on a single trip into the well, thusreducing the time and costs associated with recovery operations.Obtaining real-time high resolution imaging data during fishingoperations also enables better placement of a fishing tool on the fish,since the fishing tool can be rotated and moved axially based on theimaging data being obtained in real-time to line up the fishing toolwith the fish, allowing for quicker and more effective recoveryoperations.

Imaging Wells During Milling Operations

In some embodiments of the invention, the phased array ultrasoundimaging device described above is integrated with milling equipment toobtain real time images from within the wellbore before, during andafter milling processes. FIGS. 10A and 10B illustrate embodiments of theinvention wherein two phased array ultrasonic imaging devices areintegrated onto a milling tool.

FIG. 10A illustrates a taper mill 240 having helical teeth 240 a wrappedaround the body 240 b of the mill, and a first and second phased arrayultrasonic imaging device 244, 242 located at either end of the mill.The first imaging device 244 at the downhole end 240 c of the millpreferably has a forward facing linear transducer array for imaging avolume downhole of the tool, shown by arrows 244 a. The second imagingdevice 242 at the uphole end 240 d of the tool preferably has a radialor ring-shaped transducer array that allows for imaging of the volumelocated radially around the tool, shown by arrows 242 a.

FIG. 10B illustrates a junk mill 250 having a blade 252 with twointegrated phased array ultrasound imaging devices 254, 256. The imagingdevice 254 at the downhole end of the junk mill near the bladepreferably has a forward facing linear transducer array for imaging avolume in front of the blade shown by arrows 254 a. The second imagingdevice 256 preferably has a radial or ring-shaped transducer array forimaging a volume located radially around the tool, shown by arrows 256a.

While each of the milling tools shown in FIGS. 10A and 10B have twophased array ultrasound imaging devices, one being a forward facinglinear transducer array and one being a radial transducer arrayintegrated on the tool, it is to be understood that the tool may includeother numbers of phased array ultrasound imaging devices, for exampleonly one imaging device, or three or more imaging devices. Thetransducer arrays may also be configured in other shapes, such as lineararrays facing in other directions such as uphole or out to the side ofthe tool, or curved arrays that do not extend around the fullcircumference of the tool.

Imaging of the wellbore with the one or more imaging devices on themilling tool allows imaging to occur before, during or after millingoperations without removing the milling tool from the wellbore andwithout having to deploy a separate tool for gathering image data. Thisallows for high-quality, real-time images to be obtained in acost-effective and efficient manner. For example, as the milling tool isdeployed into the wellbore, the imaging device(s) can be used to obtaina three-dimensional image of the length of the wellbore, providingvaluable information on the condition of the casing or liner and anydebris or items located in the well. When the milling tool reaches anobstruction or debris in the well which is to be cleared, the forwardfacing transducer can provide a high-resolution image of the obstructionor debris, providing information on the type and position of theobstruction or debris which is valuable in making steps regarding themilling operation, for example the speed at which milling is to occur.The forward facing transducer can continue to provide real-time imaginginformation while milling is occurring to aid the operators in themilling process. Imaging information can also be gathered after millingis complete to confirm that the operation has been successful and toascertain whether any debris or damage exists in the wellbore.

In another example, the milling tool with one or more integrated phasedarray ultrasound imaging devices can provide imaging data before, duringand after sidetracking operations. This allows for the imaging device todetermine the shape, location and orientation of any windows that havebeen milled in the casing or completion, and any lips or features aroundthe windows that may affect subsequent drilling operations.

By integrating the imaging device with the milling tool, the need foradditional trips into the wellbore for information gathering purposes iseliminated, saving time and reducing costs. Additionally, if the millingoperation has been suboptimal, either by not fully removing the debrisor by a poorly milled window, the milling can continue without having toredeploy the milling tool after it has been removed for imagingpurposes.

Imaging During Drilling Operations

In certain embodiments of the invention, one or more phased arrayultrasound imaging devices, as previously described, are integrated intoa drill string to obtain imaging data during drilling operations. Theimaging device(s) may have forward facing transducers and/or radialtransducers that are integrated with the bottom hole assembly (BHA) ofthe drill string. FIG. 11 illustrates one embodiment of a BHA 260 havinga drill bit 260 a and integrated phased array ultrasound imagingdevices. A first imaging device 262 may be located in the drill bit andinclude a forward facing transducer array for imaging the area downholeof the drill bit as shown by arrows 262 a. A second imaging device 264may be located around the body 260 b of the BHA and include a radialtransducer array for imaging the radial area around the BHA body, shownby arrows 264 a.

By integrating one or more imaging devices on a drill string, imagingdata can be obtained on the rock that the drill string is drillingthrough. This information is useful in steering the drill and managingits speed and rotation. The data is also of use in well and completionplanning.

When a drill string is removed from a well, imaging data can also beobtained on the formation through which a borehole has just beendrilled, such as for example using the radial shaped transducer array onthe imaging device 264 in FIG. 11. Such information is valuable inplanning the remainder of the well and subsequent wells in the samearea, and can provide information on washouts and drill cutting buildup,as shown in FIGS. 12 and 13.

FIGS. 12 and 13 illustrate a borehole 266 recently drilled by a drillstring 268 having BHA 260 with a radial transducer array imaging device264 and a forward facing transducer array imaging device 262. In FIG.12, part of the borehole has been washed away creating a washout 270with a larger diameter than the rest of the borehole. As the drillstring is removed from the borehole, the radial transducer array imagingdevice 264 obtains imaging data on the entire length of the borehole,thereby providing data on the washout, including the existence of it,the location, size, and surrounding formation and fluids. This data isparticularly valuable for planning cementing operations.

In FIG. 13, drill cuttings 270 have built up in an area in the borehole.As the drill string is removed from the borehole, the radial transducerarray imaging device 264 obtain imaging data on the entire length of theborehole, thereby providing data on the drill cuttings build up.Cuttings buildup can cause the drillstring and other tools to get stuck,therefore it can be valuable to obtain information on the location andsize of the buildup, and the surrounding formation.

Although the present invention has been described and illustrated withrespect to preferred embodiments and preferred uses thereof, it is notto be so limited since modifications and changes can be made thereinwhich are within the full, intended scope of the invention as understoodby those skilled in the art.

The invention claimed is:
 1. A method for imaging an in-situ heavy oilwell production liner string comprising the steps of: a) inserting aphased array ultrasound imaging system into the well before the well isplaced on production, the imaging system including a ranging systemoperatively connected to the imaging system; b) moving the imagingsystem through the liner string in a substantially horizontal section ofthe well while activating the imaging system to generate a threedimensional image of the liner string; and c) assessing the conditionliner string using the three-dimensional image of the liner string;wherein steps a) and b) occur during one or both of ranging operationsusing the ranging system within the well as a second well is beingdrilled adjacent to the well, and after the ranging operations have beencompleted and the imaging system and ranging system are being removedfrom the well, the ranging operations including using the ranging systemto aid in locating a drill in the second well.
 2. The method as in claim1, wherein the phased array ultrasound imaging system has a ring-shapedor radial transducer.
 3. The method as in claim 1 wherein steps a) andb) are undertaken during a well completions process.
 4. The method as inclaim 1, wherein the well contains water, brine, water-based drillingmud, oil-based drilling mud or production fluids.
 5. A device forimaging an in-situ heavy oil well production liner string duringcompletions operations comprising: a body adapted for movement throughthe liner string; a downhole tractor operatively connected to the bodyfor providing motive power to move the device through the liner string;a phased array ultrasound imaging system operatively connected to thebody for generating a three-dimensional image of the liner string thatcan be used to assess the condition of the liner string; and a rangingsystem operatively connected to the body for guiding a drill in a secondwell as the second well is being drilled.
 6. The device as in claim 5,wherein the phased array ultrasound imaging system has a ring-shaped orradial transducer.
 7. The device as in claim 5, wherein the rangingsystem includes a ranging magnet.